It does depend on what brand ...

It does depend on what brand CEDI you have, however the next question is this:

Did you carefully follow the OEM requirements during installation?  Did you check and correct end plate bolt torque settings after moving the stacks into position?  If not, any leaking will not likely be fixable at this point due to infiltration of resin into the compartment spacer interstitial seals.

If you have a loose hose adapter or pipe adapter on the stack, it could make the leak appear to be coming from the frame.  Check carefully the source of the leak again, and tighten any loose adapters.  This has nothing to do with upset in feed water quality.